The present invention relates to the field of instrumentation used by scuba divers and, more particularly, to satellite based global positioning systems adapted for use by divers for use while underwater and integrated into the diver""s array of instrumentation.
Recreational diving has undergone a remarkable transformation over the years. In its infancy, a diver would simply strap on an air tank, depth gauge, watch, and compass, and venture off underwater. Interest in photography, marine biology, archeology, treasure hunting, and wreck diving drew millions of people underwater and led to the development of underwater still and video cameras, sonar-based ranging systems, and computer-based decompression gauges.
But methods for navigating while underwater remain primitive at best. Some divers simply surface to get their bearings, but this practice can be dangerous in areas with heavy marine traffic, or if decompression is needed. Moreover, visual sightings can sometimes be difficult to acquire at night, or in fog or rough seas. Still other divers count kick strokes along a compass heading and plot vectors on an underwater slate. But this method is cumbersome and inconvenient, and usually not very accurate, especially if currents and tides are present.
An extraordinary development in navigation is that of the satellite based global positioning system (GPS). GPS allows navigation with an accuracy to within a few meters and would provide an outstanding navigation system for divers. Unfortunately, GPS signals do not travel through water and, thus, GPS has not been directly used underwater.
So there is a need for a navigational system that can be used by a diver while underwater. It would be particularly advantageous if such a system were affordable to the average diver and would integrate into the assortment of instrumentation now used by divers.
It is an object of the present invention to provide a diver with means to determine his or her position while underwater.
It is still another object of the present invention to provide a diver with an affordable means to navigate while underwater.
It is still yet another object of the present invention to provide a diver with means to integrate GPS navigation into other instrumentation.
The present invention meets its objectives by providing a GPS system wherein the GPS antenna is above water while the navigational display is below water. In one embodiment, the GPS antenna is carried on a tow-able buoy having a diver-down flag. In another embodiment, the GPS antenna is carried by the diver and released to float to the surface when the diver wishes navigation data. In a preferred embodiment, a handheld computer not only provides an underwater GPS graphics display, but also calculates decompression information and manages data in an integrated fashion.
Further characteristics and advantages will become apparent from a description of the preferred embodiments given hereinafter.